Composition for a planographic image-forming pencil



Patented Apr. 7, 1953 coMPos'rrIoNron A PLANOGRAPHIC IMAGE-FORMINGPENCIL Charles HQVan Dusen, Jr., Willoughby, Ohio, and Oscar E.Weissenborn, Verona, N. J., "assignor's to =Addressograph MultigraphCorporation, WilmingtomDeL, a corporation of Delaware "NoDrawing.Application -May 18, 1951, a Serial No. 227,104

:2 Claims. 01. 106- 19) application is a continuation-in-part of iou rco -(pending application Serial No. 48,531, filed september 9,"l948,Patent No. 2,566,754,:and ilillfifle d "F- Planographic Image-Forming-Pencil and LeadTherefon Thisinvention relates-to aplanographicimagef'ormi'n'g pencil and to 'a so-called lead 'or writing rod thereforfor use in forming plan'ographic images uponmaster planographic printingplates including aluminum and paper or like cellulose base masterplanographic printing plates. fli numberof problems are "encountered inthe manufacture of *planographic image-forming "writingrodsbr so-calledleads and pencils em- Fbo'dying the same which are :peculiar to suchip'lanographic image-forming pencils and which =are not encountered inthe manufacture of common so-called lead pencils. Among these problems"are: A 'plan'ographic image-forming pencil must be capable :of formingan inscription or image'which will produce a satisfactory number orcopies from the master plate upon which the image is written; itmust becapable of making uniform lines, that is to say, lines which are ofsubstantially uniform width throughout their entire length upon themaster plate; the writmg instrument, that is to say, the substantiallycylindrical writing rod or so-called lead which is embodied inisuchapla'nographic pencil must be neither too soft so that the inscriptionor image formed thereby will wash off the plate readilyzor so thatitwill produce lines which will vary in width as the pencil moves across amastr aluminum or paper or'like planographicplate on which it is beingused to write an image, and

' it must n'otbe sufficiently hard to scratch such masterplanographicprinting plate; and it "must have "good ink-receptive and ink-retentiveproperties "so that it will be receptive to and will I retain thelithographic "inks used in making reproductions from the master plate.

Accordingly, an object of the present invention is to provide 'a new andimproved image-form'- ing. planographic pencil embodying a writinginistrumentorso-called lead which has-good image- ;forming propertiesand which will produce images havingzgood ink-receptive andink-wretentivepropi'rihich 'is' suflicientlyhard to enable it to make f;rm width upon a -paper or other graphi printing plate and to prevent theIi made hereby from washing on the plate;

eities.11for planogr'aphicor lithographic inks? object er the nventi nis it prance 1 cylindrical writing rods or-so-called lea'ds of the newplanographic pencil.

V :A further object of the inventionfis to anew and improvedplanographic image-forming lead or writing instrument for use ina'planographic image-forming pencil which may be employed in aplanographic image-forming pencil of any suitable character includingthose "of the mechanically propelled type. I i:

Other and further objects of the present'im 'vention will be apparentfrom the followi'ngdescription and claims which describe "preferredembodiments of the invention and the principles thereof and what we nowconsider to be the best mode in which we have contemplated apply- 7invention, may be that which is shown in the following example:

Example-No. 1

Partsbyweiht Nigrosine I v 35 Japan wax p 2 Aluminum stearate e 40Methyl cellulose solution (binder) (one part dissolved in six parts ofwatenby weight) g 27.6

In the manufacture of the new planographic image-forming pencil, and thenew plano'graphic image-forming lead or writing rod therefor, then'igrosine and aluminum s'tearate referred 'toin the foregoing Example'No. 1 may be mixed together in the dry state and the methyl "cellulosemay be dissolved in approximately six times "its weight of water,whereupon the 'nigrosine-aluminum stearate mixture and the a'queousmethyl cellulose binder solution may be thoroughly mixed for a period oftwo or three hours, in a suitable mixer. The Japan wax may then bemelted to liquid form and added to the aforesaid mixture of nigrosine,aluminum 'stearate andmethfyl cellulose binder and the "resultingmixtureffur their thoroughly mixed for a period of swan-tars. Theresulting base mixture is of dougf sistency and may be rolled and examsform of substantially eyup-ar'icai was I to suitable lengths to form thenew pla'nog' 'phlc The thus prepared planographic image-form ing leadsor substantially cylindrical rods may then be encased or enclosed ingrooved wooden pencil casings in a conventional manner. This operation,as is well understood in the art, includes inserting the substantiallycylindrical writing rods or so-called leads into a groove formed in oneof two complementary sections of a wood or like pencil casing,adhesively securing the two complementary halves or sections of thepencil casing together with the substantially cylindrical writing rod orso-called .leadtherebetween; suitably shaping the outer -surface of thepencil casing as by forming hex- \agonal faces thereon; and thensuitably finishing :the pencil casing as by sanding and painting thesame.

' In addition to being encased in a grooved wooden casing the newplanographic image- {forming leads or writing rods may, if desired, beemployed in pencils of the mechanical type. It will thus be seen thatthe new planographic image-forming writing rods or so-called leads'which are prepared according to the foregoing Example No. 1, arecomprised of the dried reaction product of an intimate mixture of anaquelous solution of a binder, namely, a solution of ,methyl cellulosein water, and the balance a lmixture of the solid materials referred toin the foregoing Example No. 1, namely, nigrosine, Japan wax andaluminum stearate.

In place of the Japan wax specified in the foregoing Example No. l wemay employ suitable equivalent quantities of one of the following sub-Tstances or mixtures thereof, namely, tallow, stearic acid, carnaubawax, bees wax, parafiin ,wax, and spermaceti.

1 The aqueous solution of methyl cellulose (binder) specified in theforegoing Example No. 1 may be employed within a rather wide range offrom approximately ten per cent to approximately fifteen per cent, byweight, of the com- ;plete pencil base mixture. However, it; has beenfound that the resulting planographic imageforming pencil or writing rodbecomes too weak if the percentage of the aqueous methyl cellulosebinder is reduced below the minimum of ten percent, as specified,whereas if the percentage of the aqueous methyl cellulose binder isincreased substantially in excess of the maximum of fifty per centspecified the writing or planofgraphic image-forming qualities of theresulting pencil or writing rod are unsatisfactory.

i vIn place of the aqueous solution of methyl ,cellulose specified inthe foregoing Example No. l suitable equivalent quantities of thefollowing -materials, or mixtures thereof, may be employed as thebinder, namely, ethyl cellulose, carboxyl methyl cellulose, gumtragacanth, polyvinyl alcohol and clay.

Indulin may be employed in place of the nigro- :sine specified in theforegoing Example No. l in place of the aluminum stearate specified wealso employ suitable equivalent quantities of lcalcium stearate or zincstearate, or mixtures of ,these materials. l v 1, .Another composition.which may be employed Lill preparing the base for the newsubstantially-- 4 cylindrical planographic image-forming pencils orwriting rods is illustrated in the following example in which all partsindicated are by weight:

Example No, 2

Parts by weight Nigrosine 35 Aluminum stearate 25 Inert mineral material(clay) 15 Methyl cellulose solution (binder) (one part dissolved in sixparts water, by weight) 27.6

cal planographic image-forming Writing rod or instrument for the newplanographic imageforming pencil enables a planographic imageformingpencil embodying the new planographic image-forming pencil or writin rodto slide or move easily over the surface of a planographic printingplate during the writing or image-forming operation; the nigrosine (orindulin substituted therefor) is an image-forming material and impartsnecessary color to the substantially cylindrical planographicimage-forming writing rod or instrument, namely a black color; thealuminum stearate, or other material substituted therefor, is also animage-forming material; and the methyl cellulose, with or without clay,serves as a binder to bind the various ingredients together.

The clay specified in the foregoing Example No. 2 serves as an inertmineral filler, adding bulk to the mixture and diluting theconcentration of the nigrosine and aluminum stearate and it may alsofunction as a binder. Such clay may be china clay or English clay or inplace thereof talc or any other suitable inert filler material may beemployed to add bulk to the mixture and also serve, in part, as abinder, if desired.

It has been found that the new planographic image-forming so-calledleads or writing rods prepared according to the present invention havegood image-forming properties, and that images formed thereby have goodink receptive properties for lithographic inks; that they aresufficiently hard to enable it to form good images, including lines ofuniform width, on paper and like planographic printing plates; that theyprovide images which will not readily wash oil such plates; and thatthey provide images which will enable satisfactory editions or numbersof copies to be reproduced from a master paper or like planographicprintin plate when the latter is employed in making reproductions in arotary and improved planographic image-formingpenoil, and a new andimproved planographic image- .forming writing rod or instrument for usetherein, and a novel composition for making the same,

and that the invention has the desirable advantages and characteristics,and accomplishes its intended objects, including those hereinbeforepointed out and others which are inherent in the invention.

We claim:

1. A planographic image-forming pencil writing material consistingessentially of the dried productof an intimate mixture of the followinmaterials within a range of plus or minus ten per cent of each of thequantities specified, all parts being by weight:

Nigrosine 35 Aluminum stearate 25 Inert mineral material 15 Methylcellulose solution (one part dissolved in six parts of water, by Weight)27.6

2. A planographic image-forming pencil writing material consistingessentially of the dried product of an intimate mixture of the followingmaterials within a range of plus or minus ten Nigrosine 35 I Aluminumstearate 25 Clay 15 I V 6 7 per cent of each of the quantitiesspecified, all parts being by weight:

Methyl cellulose solution (one part dissolved in six parts of water, byweight) 27.6

CHARLES H. VAN DUSEN, JR. OSCAR E. WEISSENBORN.

REFERENCES CITED The following references are of record in the file ofthis patent:

1. A PLANOGRAPHIC IMAGE-FORMING PENCIL WRITING MATERIAL CONSISTINGESSENTIALLY OF THE DRIED PRODUCT OF AN INTIMATE MIXTURE OF THE FOLLOWINGMATERIALS WITHIN A RANGE OF PLUS OR MINUS TEN PER CENT OF EACH OF THEQUANTITIES SPECIFIED, ALL PARTS BEING BY WEIGHT: